usefulness of coronary computed tomography angiography for early triage of patients with acute chest...
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Usefulness of Coronary Computed Tomography Angiography For Early Triage of Patients with Acute Chest Pain - The Rule Out Myocardial
Infarction Using Computer Assisted Tomography (ROMICAT) Trial
Udo Hoffmann, Fabian Bamberg, Claudia U. Chae, John H. Nichols, Ian S. Rogers, Sujith K. Seneviratne, Quynh A. Truong, Ricardo C. Cury, Suhny Abbara, Michael D. Shapiro, Jamaluddin Moloo, Javed
Butler, Maros Ferencik, Hang Lee, Ik-Kyung Jang, Blair A. Parry, David F. Brown, James E. Udelson, Stephan Achenbach, Thomas J.
Brady, John T. Nagurney
Department of Radiology, Emergency Medicine, and Cardiology Division, Massachusetts General Hospital and Harvard Medical School, Boston MA
Research Grants: Siemens Medical Solutions, Amersham/GE Healthcare, Bracco Diagnostics, NIHAdvisory Boards: Vital Images, Bayer Healthcare/Siemens Medical Solutions
Disclosures
Early Risk Stratification and Triage in the ED
- 6 Million present with chest pain to ED annually- - ECG, initial biomarkers, and clinical presentation and traditional risk factors – no safe triage possible (Nagurney, JAMA 2006)
- low threshold to admit, >80% have no ACS, $8Billion annually healthcare cost
- 1-5% of missed ACS cause 20% of ED malpractice costs
Improvement of the initial ED evaluation needed!
Preliminary coronary CTA Studies
- coronary MDCT is feasible in the acute care setting
- low to intermediate risk patients - absence of CAD has 100% NPV for ACS – found in 40% of patientsHoffmann et al Circulation 2006
- very low risk patients - CT may be cost saving alternative to myocardial perfusion stress testing Raff et al JACC 2007
- normal coronary CTA has excellent NPV for MACE within 15 months Rubinshtein et al. Circulation 2007
Remaining Questions for Patient Management
1. Confirmation in larger cohorts
2. Safety of Stenosis based Triage
3. Relevance of detected Stenosis
4. Incremental Value of non-calcified plaque for exclusion of ACS
ROMICAT I - Specific Aims
1. Determine the prevalence of coronary atherosclerotic plaque and stenosis in patients with acute chest pain and low to intermediate for ACS
2. Determine the diagnostic accuracy of these findings for ACS
3. Determine whether this information is incremental to current risk assessment
ED tAcute Chest Pain
Neg. ECG
Neg. Trop
Index Hospitalization
Observational, double-blinded Cohort Study
Cardiac CT Analysis - blinded to caregiver and subjects
1. Presence of atherosclerotic plaque per coronary segmenta. Calcified plaqueb. Non-calcified plaque
2. Presence of significant coronary artery stenosis (>50%)
6 month FUStandard clinical care
ROMICAT I – Study Design
Inclusion Criteria- >5 min of chest pain <24h- Normal initial Biomarker- Admitted to Rule out MI- Normal sinus rhythm
Exclusion Criteria
- positive initial Troponin
- Diagnostic ECG changes
- Creatinine >1.3 mg/dl
- Known CAD
Primary Endpoint
ACS* (NSTEMI or UAP) during Index Hospitalization and MACE during 6-month follow-up adjudicated by independent committee
*According to AHA/ACC/ESC Guidelines
ROMICAT I - Methods
Coronary MDCT- 64-slice MDCT (Siemens, Forchheim, Germany)- Beta-Blocker if HR>65 bpm, Nitro- ~20 ml + 80ml contrast agent (Iodhexodol 320)- tube current: ~850 mAs, tube voltage: 120 kV
Protocol Eligible Subjects (n = 658)
Enrolled Subjects (n = 412)
Study Population (n = 368)
• Physician Denied (n = 19)• Patient Refusal (n = 124)• Missed to Ongoing Recruitment (n = 103)
Incomplete Scan (n=17)• Interference with Clinical Care (n = 10)• Claustrophobia/Nausea (n = 3)• Contrast Extravasation (n = 3)• Scanner Malfunction (n = 1)
Complete Scan (n=27)• History of Stent Placement (n = 10)• History of CABG (n = 17)
18 month Screening and Enrollment
ROMICAT I – Demographics and Risk Factors
Age (years, mean SD) 52.7±12
Male Gender (n, %) 223 (61%)
Race (n, %) African American Caucasian Asians Others
31 (8%)313 (85%)
4 (1%)20 (6%)
No. of risk factors (median, IQR) 2 (1)
TIMI Score (low/intermediate/high) in %
94.3/ 5.4/ 0.3
ACS during index hospitalization (%, n) Unstable angina pectoris (%, n) Myocardial infarction (%, n)
31 (8%)23 (74%)8 (26%)
MACE during six month follow- up (%, n):Recurrent chest pain:
Outpatient evaluation (PCP)Readmission without testingReadmission with testing
068 (18%)50 (74%)
5 (7%)13 (19%)
ROMICAT I – Prevalence of Plaque and Stenosis
No CAD - 50.4% (no plaque and no
stenosis)N= 185/368
Significant stenosis detected or not excluded -
18.4%N= 68/368
Non-obstructive Plaque - 31.2%
N= 115/368
CAD categories with relevance for early triage of patients with ACP in the ED
ROMICAT I – CAD and ACS
No CAD
Nonobstructive Plaque
Significant stenosis detected or not excluded
No ACS
7 ACS• non-stenotic ACS• small vessel disease
24 ACS
NSTEMI with significant stenosis
40-year old male who presented 3 hours after the onset of substernal chest pain, inconclusive initial evaluation in the ED, Troponin positive 8 hours after ED presentation, underwent invasive coronary angiography with stenting of an 80% mid LAD
NSTEMI without significant stenosis in CT
Subject Coronary CTA Finding of Non-obstructive
Plaque
Troponin Stress Nuclear Perfusion Imaging
Coronary Angiography/ Intervention
Clinical Outcome
76-year old female
prox RCA, prox LCX, and prox and mid LAD
Negative inferolateral area of ischemia
None UAP
78-year old female
LM, prox, mid, and dist. LAD; PDA
Negative inferolateral area of ischemia
None UAP
72-year old male
Mid RCA Negative apical area of ischemia, hypokinesis inferolateral region
None UAP
52-year old male
Mid LAD 2nd set pos. (+6.8h)
None 30% stenosis in mid LAD/None
NSTEMI
63-year old male
Prox and mid RCA, mid and dist. LAD
3rd set pos. (+5.7h)
None 95% PLV, 50% 1st septal branch/ stent
PLV
NSTEMI
53-year old male
LM and dist. LAD 2nd set pos. (+6.6h)
None 40% D2 ostium, 70% D3 ostium stenosis/None
NSTEMI
59-year old female
OM1 Negative None 80% PDA stenosis/ stent PDA
UAP
Subject Coronary CTA Finding of Non-obstructive
Plaque
Troponin Stress Nuclear Perfusion Imaging
Coronary Angiography/ Intervention
Clinical Outcome
76-year old female
prox RCA, prox LCX, and prox and mid LAD
Negative inferolateral area of ischemia
None UAP
78-year old female
LM, prox, mid, and dist. LAD; PDA
Negative inferolateral area of ischemia
None UAP
72-year old male
Mid RCA Negative apical area of ischemia, hypokinesis inferolateral region
None UAP
52-year old male
Mid LAD 2nd set pos. (+6.8h)
None 30% stenosis in mid LAD/None
NSTEMI
63-year old male
Prox and mid RCA, mid and dist. LAD
3rd set pos. (+5.7h)
None 95% PLV, 50% 1st septal branch/ stent
PLV
NSTEMI
53-year old male
LM and dist. LAD 2nd set pos. (+6.6h)
None 40% D2 ostium, 70% D3 ostium stenosis/None
NSTEMI
59-year old female
OM1 Negative None 80% PDA stenosis/ stent PDA
UAP
NSTEMI with small vessel disease
59-year old female with typical chest pain, non-diagnostic ECG and negative serial Troponin, coronary CTA – plaque in OM 1, invasive coronary angiography demonstrates 95% stenosis of the PDA
NSTEMI with PDA stenosis
ROMICAT I – Diagnostic Accuracy
Sens: 100% (0.88-1.00)
NPV: 100% (0.98-1.00)
Spec: 54% (0.49-0.60)
PPV: 17% (0.12-0.23)
ACSNo
ACS
Plaque
No Plaque
31 154
0 183
Sens: 77% (0.59-0.90)
NPV: 98% (0.95-0.99)
Spec: 87% (0.82-0.90)
PPV: 35% (0.24-0.48)
ACSNo
ACS
Sign. Stenosis
No Stenosis
24 44
7 293
1. Triage Criterion: Presence of any plaque
2. Triage Criterion: Presence of significant Stenosis (>50%)
Results – Stenosis and ACS
• specificity of significant stenosis for ACS was lower in subjects ≥65 years of age (58% vs. 91%) because of increased prevalence of CAC (84% vs. 39%; p<0.0001)
• in 34 patients a significant stenosis was detected• 20 had ACS• 14 had no ACS or MACE after 6 months
severe RCA lesion, no regional LV dysfunction, normal stress SPECT study,diagnosis of ‘non cardiac chest pain’.
Incremental Value of coronary CTA to TIMI
AUC for the detection of ACS during index hospitalizationExtent of plaque, presence of stenosis, TIMI risk score (AUC: 0.88, 0.82 vs. 0.63; respectively, all p<0.0001).
Summary
- confirmation - Absence of any CAD in 50% of patients - 100% NPV for ACS – may enable early safe and early discharge from the ED
- triage criterion of 50% stenosis is not perfect because of non-stenotic ACS and limited spatial resolution of coronary CTA
- significant stenosis is detected in 10% of patients by coronary CTA – about 40% of these were discharged with a diagnosis of non-cardiac chest pain
- incremental value of non- calcified plaque for early triage is limited
Thank you!
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